Java‑to‑PYI is a Rust tool that parses Java source into a preprocessed AST and generates Python stub files (.pyi) with type definitions only. It was originally designed to generate class declarations to provide accurate type hints in the Telegram codebase when developing Exteragram plugins.
cargo install java2pyi
- Clone this repo
git clone https://github.com/n08i40k/java2pyi
- Compile and install
cargo install --path .
- Clone OpenJDK source code (required for all use-cases, otherwise, non-promitive java types won't be resolved)
git clone https://github.com/openjdk/jdk
- Remove sample file from OpenJDK source code
rm ./jdk/src/java.base/share/classes/java/lang/snippet-files/ProcessExamples.java
- Clone Telegram for Android source code
git clone https://github.com/DrKLO/Telegram
- Create directory for stub files
mkdir stubs
- Start generator
java2pyi -i ./jdk/src/java.base/share/classes/java/ -i ./Telegram/TMessagesProj/src/main/java/ -o ./stubs
Where -i is directories with .java files and -o is output directory for generated stubs.